Hermetically sealed motor compressors particularly suitable for small refrigerating machines



June 1965 K. v. VALBJQRN 3,

HERMETICALLY SEALED MOTOR CQMPRESSORS PARTICULARLY SUITABLE FOR SMALL REFRIGERATING MACHINES Filed Sept. 4, 1962 2 Sheets-Sheet 1 June 1965 K. v. VALBJQRN 3, 87,

HERMETICALLY SEALED MOTOR COMPRESSORS PARTICULARLY SUITABLE FOR SMALL REFRIGERATING MACHINES Filed Sept. 4, 1962 2 Sheets-Sheet 2 United States Patent HERMETICALLY SEALED MGTGR QTGMPRES This invention relates to a hermetically-sealed motor compressor and is more particularly concerned with a motor compressor especially suitable for small refrigerating machines and having a vertical shaft with the compressor disposed at the top. 7

The lower end of the shaft of machines of this type is usually provided with a pump for drawing oil from the oil pan in order to lubricate the motor compressor. The oil flowing from the upper part of the shaft bearing and from the crank pin hearing, as well as the excess oil flowing away from an opening in the bottom part of the crank pin, is forced outwards because of centrifugal force and thus return-s to the oil pan.

It is an object of this invention to provide a construction in a motor compressor of the type described whereby the oil is utilized for cooling purposes before it flows back to the oil pan.

In accordance with this invention, there is provided in combination with the motor compressor a fixed oil collecting device which at least partly surrounds that part.

of the crank-shaft projecting above the shaft bearing. This oil collecting device picks up the ejected oil, which then is used for cooling the motor compressor. During lubrication, the oil absorbs some heat from the motor compressor, but as it is ejected from the lubricated parts, the oil still has a temperature which is sufiiciently low that the oil can be effectively utilized to further cool the motor compressor.

In accordance with one of the embodiments of the invention, the lower end of the oil collecting device has oil drains which, in their simplest form, can consist of slots between the oil collecting device and the motor support. By providing the oil collecting device with drop holes or by providing the support with grooves, it is possible to use the oil forced through the slots and, therefore, flowing over the rather large surface of the motor support, as a supplementary and efficient cooling medium.

According to another embodiment of the invention, the oil drains can be located within the portion of the motor support enclosed by the oil collecting device. In this case, the oil is led to the motor and thus provides a supplementary cooling of the motor and, by installing a fan of well-known type below the oil drains, which is advantageous in this case, the greater part of the oil is blown over the stator ends and thereby provides cooling of these parts.

The oil collecting device has still another advantage. It has been established that the oil atomized inside the capsule is deposited on the pressure line or on the pres sure muifier located in the pressure line, thus absorbing a considerable amount of heat present in these elements. Such heat absorption is not only not necessary, but is directly disadvantageous because the heat thereby remaining inside the capsule thus increases the overall temperature level of the capsule. According to this invention, the pressure line and/ or the pressure muffler of the compressor can be located outside the oil-collecting device. As a rcsult,[the ejected oil will no longer come into contact with these parts.

In prior constructions, some obstructions have been located in the trajectory of the oil forced from the machine, for example the normal components of the motor Fatented June 8, 1965 compressor, such as the cylinder block, which have partially blocked this trajectory.

Accord-ing to the present invention, the oil-collecting device can be combined with such components and it is thus possible to collect a considerable amount of oil which can be used for cooling purposes.

Further characteristics of the invention will appear from the following description of illustrative embodiments, taken in connection with the accompanying drawings wherein,

FIG. 1 is a longitudinal sectional view of a motor compressor provided with an oil-collecting device embodying features of the present invention;

FIG. 2 is a plan view of the construction shown in FIG. 1, but with the capsule cover removed; and

FIG. 3 is a fragmentary view of another embodiment, seen from the side and partly in section.

In FIGS. 1 and 2, the motor compressor is contained in a capsule or casing 1, hermetically-sealed by means of the cover 2, and is secured to the capsule by means of springs 3 which engage the supporting element 4 which contains the stator 5 of the electric motor. The rotor 6 is secured upon the motor crank-shaft 7 which is supported in the bearing 8 formed by the supporting element 4. The crank pin 9 of crank-shaft 7 engages the sliding block it) of crank cross-head 11, thus activating the piston 12 which is adapted to reciprocate in the diagrammatically-illustrated cylinder 13.

The motor crank-shaft 7 has an axial bore 14 extending almost its entire length, as well as an inclined outwardly-directed bore 15 which is connected at one end with the bore 14. The hollow conical part 16 of the centrifugal pump disposed at the lower end of the shaft 7 raises the oil from the oil pan 17, then forces it through the inlet connection 18 to the lubricating groove 19 of the shaft bearing, and through the connecting bore 20 to the lubricating groove 21 of the crank-pin hearing.

The oil emerges at A, near the lower end of the shaft, and at B at the upper end of the shaft, as Well as at C at the lower end of the crank-pin bearing and at D at the upper end of this bearing. Finally, the oil emerges at B through the bore 15 in the top part of the crank pin. Centrifugal force influences the flow of the oil at all of these points and forces the oil out of the lubricated mechanism. This action is most vigorous adjacent the crank pin which is disposed above the shaft bearing 8 because the eccentricity of the crank pin 9 and the counterweight 22 at this point causes a larger centrifuging of the oil.

According to the invention, the oil-collecting device comprises a plate 23, which extends vertically and which surrounds the part of the crank-shaft 7 which projects above the shaft bearing 8. i

This plate intercepts and collects the oil issuing from the points B, C, D, and E and permits it to pass through the lower outlet openings 24 in the supporting element 4 to the interior of the motor. At the outlet openings the oil is acted upon by the fan 25 which is disposed below the openings 24, and is forced outwardly. The major amount of the oil is forced out the slot 26 formed between the supporting element 4 and the windings 27. A minor amount is forced through the air gap 28 between the stator and the rotor. The cooling effect thus achieved is substantial.

The oil-collecting plate 23 surrounds the shaft 7 along an angle of more than and is supplemented by the side structures 29 of the cylinder 13 in which the muflier is located in well-known manner. In this manner, it is possible to collect the entire amount of oil forced out of the mechanism and to reuse this oil for cooling purposes.

The pressure line 31, issuing from the cylinder-head a 0.9 349, and which contains the pressure muffler 32 and a corrugated section 33 which serves to equalize the displacement between the motor compressor and the outlet opening 34-, is led outside the oil-collecting plate 23. Thus, the entire pressure line is protected against being wet by the oil and only a slight amount of heat is transferred to the interior of the capsule.

In the embodiment'of FIG. 3, the supporting element 35 has no'oil-discharge openings at its center comparable to the openings 24 of the element 4 of FIGS. 1 and 2 and is shown in elevation. The oil-collecting plate 36, however, is shown in section. In order to simplify illustration, all components of the motor compressor, with the exception of the shaft 37 and its crank pin 38 and the sliding block 39, have been omitted. The oil-collecting plate 36 is provided at its lower end with a discharge outlet 4t), enabling the collected oil to flow over the inclined area 41 of the supporting element 35, which thus is cooled.

It will be understood that the motor and compressor shown in the drawing are merely illustrative and that the cooling system invention may be embodied in various motor-compressor systems of known construction in which oil issues from the top of the lubricated mechanism. The motor and compressor can also, for example, be of the construction shown in co-pending application, Serial No. 173,847, filed November 13, 1961, and in copending application, Serial No. 176,464, filed November 27, 1961.

It will also be understood that various changes and modifications may be made in the embodiments described above and illustrated in the drawing without departing from the scope of the invention as defined in the appended claims.

It is intended, therefore, that all matter contained in the foregoing description and in the drawing shall be interpreted as illustrative only and not as limitative of the invention. a

I claim:

1. In a hermetically-sealed motor-compressor unit particularly adapted for small refrigerators, the combination of a sealed chamber having a lower end portion providing an oil pan, an electric motor mounted in said chamber with its axis vertical, said motor comprising a stator and a rotor with a vertical shaft having at its upper end an eccentric crank portion, a compressor mounted in said chamber above said motor and comprising a horizontal cylinder and a piston reciprocable in said cylinder and operably connected with said eccentric crank portion for reciprocation thereby, said connection including a hearing, ahot gas pressure line extending from said compressor to the exterior of said chamber, said shaft having an oil channel therein extending from the lowerend of said shaft to said bearing, an oil pump at the lower end of said shaft for pump-ing oil from said pan to said hearing and vertical oil-collecting plate means disposed around but spaced from said bearing and together with said cylinder substantially surrounding said hearing so as to prevent oil being thrown onto said hot gas pressure line from said crank portion and bearing and to collect oil thrown off by centrifugal force from said crank portionand bearing and direct said collected oil over the motor to cool the motor.

2. A motor-compressor unit according to claim 1, in which said hot gas pressure line extend-ing from said compressor to the exterior of said chamber at least partially encircles said oil-collecting plate and is disposed relative to said plate so that said plate prevents oil being thrown onto said hot gas line from said crank portion and bearing.

3. In ahermetically-sealed motor-compressor unit particularly for small refrigerators; the combination of a d sealed chamber having an oil pan at its'bottom, an annular support member spring mounted in said chamber between its top and bottom, an electric motor comprising a stator mounted on said support and a rotor having a vertical shaft extending up through said support and having at its upper end an eccentric crank portion, a compressor comprising a cylinder mounted on said support and a piston reciprocable in said cylinder and operably connected with said eccentric crank portion for reciprocation thereby, said connection including a bearing, said support having a central funnel portion surrounding said shaft, said shaft having an oil channel therein extending from the lower end of said shaft to said bearing, an oil pump at the lower end of said shaft for pumping oil from said pan to said bearing and a vertical oil-collecting plate disposed around but spaced from said bearing and together with said cylinder substantially surrounding said hearing so as to collect oil thrown off by centrifugal force from said crank portion and bearing and directing said collected oil into said funnel portion of said support. 4. A motor-compressor unit according to claim 3, in which there is an annular space between said support and an upper portion of said stator.

5. A motor-compressor unit according to claim 4, further comprising a fan on said shaft below said funnel portion of said support and directed upwardly so that oil flowing downwardly through said funnel portion is at least in part blown upwardly by said fan through said annular space between said support and said stator.

6. In a hermetic refrigeration compressor comprising a hermetically sealed casing, a refrigerant compressor in said casing, a lubricating device for lubricating said compressor comprising means to discharge through space interiorly of said casing a liquid lubricant for lubricating working parts of said compressor and cooling said parts, hot gas conduit means for discharging hot gaseous refrigerant from said compressor and easing after com pression of said gaseous refrigerant, a shield disposed for precluding lubricant from coming into contact with said hot gas conduit means thereby to preclude heat transfer from said conduit means to said lubricant by at least contact therewith.

7. In a hermetic refrigeration compressor comprising, a hermetically sealed casing, a compressor in said casing for compressing a gaseous refrigerant, a lubricating device for lubricating said compressor comprising a driven shaft having an upper portion comprising a lubricant outlet for discharging liquid lubricant therefrom through space interiorly of said casing for lubricating said compressor, discharge conduit means for discharging to the exterior of said'casing hot gaseous refrigerant from said compressor after compression, a shield disposed for deflecting said lubricant discharged through space in said casing to preclude said lubricant discharged from said outlet from coming into contact with said discharge means thereby to preclude transfer of heat to said lubricant from said gaseous refrigerant after compression.

8. In a hermetic refrigeration compressor according to claim 7, in which said discharge conduit means is disposed spaced apart from said driven shaft and is in contact only with said compressor interiorly of said cas- ,ing to preclude heat transfer 'bycontact.

References Cited by the Examiner UNITED STATES PATENTS 2,100,716 11/37 Lipman 230139 X 2,178,811 11/39 Sateren 230206 X 2,199,415 5/40 Philipp.

LAURENCE v. EFNER, Primary Examiner.

ROBERT M. WALKER, Examiner. 

1. IN A HERMETICALLY-SEALED MOTOR-COMPRESSOR UNIT PARTICULARLY ADAPTED FOR SMALL REFRIGERATORS, THE COMBINATION OF A SEALED CHAMBER HAVING A LOWER END PORTION PROVIDING AN OIL PAN, AN ELECTRIC MOTOR MOUNTED IN SAID CHAMBER WITH ITS AXIS VERTICAL, SAID MOTOR COMPRISING A STATOR AND A ROTOR WITH A VERTICAL SHAFT HAVING AT ITS UPPER END AN ECCENTRIC CRANK PORTION, A COMPRESSOR MOUNTED IN SAID CHAMBER ABOVE SAID MOTOR AND COMPRISING A HORIZONTAL CYLINDER AND A PISTON RECIPROCABLE IN SAID CYLINDER AND OPERABLY CONNECTED WITH SAID ECCENTRIC CRANK PORTION FOR RECIPROCATION THEREBY, SAID CONNECTION INCLUDING A BEARING, A HOT GAS PRESSURE LINE EXTENDING FROM SAID COMPRESSOR TO THE EXTERIOR OF SAID CHAMBER, SAID SHAFT HAVING AN OIL CHANNEL THEREIN EXTENDING FROM THE LOWER END OF SAID SHAFT TO SAID BEARING, AN OIL PUMP AT THE LOWER END OF SAID SHAFT FOR PUMPING OIL FROM SAID PAN TO SAID BEARING AND VERTICAL OIL-COLLECTING PLATE MEANS DISPOSED AROUND BUT SPACED FROM SAID BEARING AND TOGETHER WITH SAID CYLINDER SUBSTANTIALLY SURROUNDING SAID BEARING SO AS TO PREVENT OIL BEING THROWN ONTO SAID HOT GAS PRESSURE LINE FROM SAID CRANK PORTION AND BEARING AND TO COLLECT OIL THROWN OFF OF CENTRIFUGAL FORCE FROM SAID CRANK PORTION AND BEARING AND DIRECT SAID COLLECTED OIL OVER THE MOTOR TO COOL THE MOTOR. 